<html>
    <head>
        <title>
            js tools
        </title>
        <script type="text/javascript" src="jquery-3.2.1.min.js"></script>
        <style type="text/css">
            h1 {color:red}
            p {color:blue}
        </style>
    </head>
    <body>
        <h1>hello</h1>
        <p> is a js tools;</p>
        <button onclick="clicks()">click</button>
        <script>
            function clicks() {
                alert('hello world');
            }
        </script>
    </body>
</html>